1/2  cup melted butter (1 stick)
2   cups dark brown sugar
2   eggs
1 1/2  cups flour
2  teaspoons baking powder
1  teaspoon vanilla
    pecans (optional)

Preheat oven to 375.
Butter a 9-inch square cake pan.
Mix all ingredients together combining them well.
Spread the mixture in the cake pan and
bake for 35 to 40 minutes,
or until dry on top and almost firm to the touch.
Let cool for 10 to15 minutes,
then cut into squares.